The first record of a terrestrial crustacean, Porcellio scaber (Isopoda, Porcellionidae), from sub-Antarctic Marion Island

Here we present the first record of Porcellio scaber Latreille, 1804 (Isopoda, Porcellionidae) from sub-Antarctic Marion Island. Because surveys for new species introductions are undertaken on a regular basis (at least annually) on the island, it seems likely that the species arrived in April 2001. The present distribution of P. scaber at the station suggests that it probably arrived with building supplies from Cape Town, although it may have been introduced from Gough Island from where it is also known. The species feeds on detritus as it does elsewhere, and appears to be reproductively most active over the summer months from October until March. The introduced house mouse and indigenous lesser sheath-bill, the main vertebrate predators of invertebrates at the island, would not take individuals of P. scaber. The introduction of this highly successful invasive species at Marion Island highlights the ongoing conflict between use and conservation on the Southern Ocean islands.